This invention relates to the art of perforating sheet material, and more particularly to a new and improved method and apparatus for providing closely spaced small diameter holes in sheet material such as conveyor belts.
One area of use of the present invention is in micro-drilling a series of closely spaced holes in a conveyor belt to a facilitate passage of air through the belt thus providing suction and vacuum hold-down of items such as sheet material carried on the conveyor belt. By way of illustration, such conveyor belts in vacuum hold-down apparatus used in the cloth cutting industry have very dense hole patterns, i.e. nearly a million small diameter closely spaced holes in a belt six feet wide and fifty feet long. In addition to the ability to provide even smaller diameter holes in closer spaced relation, an important consideration is providing the holes in a manner that does not impart structural weakness in the belt.